What would cause my front wheels to lock up after turning sharply to back into a parking spot there was there was a loud thump and and they locked up and won't move now

What is your question?

I turn the wheel sharply to back into a parking space there was a clunk and the front wheels locked up what would cause that when I tried straightening out it would unlock for a second but then it would lock back up again I tried backing up and it locked up I tried going forward and it locked up also when I turn the wheel it locks up instead staying locked up now

What makes this problem better or worse?

Turning the steering wheel left or right even a little bit

How long has your 2001 Ford Explorer Sport Trac had this problem?

It just happened last night